(a) Field of the Invention
The present invention relates to a flat panel display device. More specifically, the present invention relates to a flat panel display device for various input signals providing an optimized configuration of integration, structure and production of the flat panel display device.
(b) Description of the Related Art
In the 1990's, production of display devices such as CRTs, LCDs, PDPs and ELs became very competitive, developing markets and prototypes.
For example, the LCD is generally used for portable screens of under 13″ and the CRT for a monitor screen of 15 to 20″ at present, but it is supposed that these other devices will compete with the TFT LCD, and the CRT will continuously take the lead in the market of television sets of 20 to 30″. But if the display features and process of Plasma Addressed LCD (PALCD) or TFT LCD become advantageous to users, the situation may change. Also, in the display market of screens of 30 to 40 inches, the CRT and PDP will compete, and in the display market of screens of over 40 inches, conventional type PDPs, projection type LCD projectors, CRT projectors and DMD projectors will compete.
Also, the inorganic ELs have military instrument markets, the LCDs have indoor and interactive display markets, and the organic ELs and FEDs are being researched as next generation display devices.
As described above, the display device markets are gradually switching to flat panel display devices with larger screens and slimmer thickness.
The LCD monitor, which is an example of common flat display devices, comprises an LCD module, an inverter for providing back light, and a signal processing printed circuit board (PCB) for receiving analog R, G and B signals, video signals such as NTSC and digital signals such as the transition minimized differential signaling (TDMS) signals, and performing signal processing such as scaling and on screen display (OSD) functions.
However, since the signals are transmitted between the PCB and the inter-board via the TTL signal method, EMI problems occur. Particularly, since high-speed signals are transmitted between a signal processing PCB and an LCD control PCB, and because of differences of common ground levels of the different PCBs, the LCD monitor has an EMI problem.
To solve the above-noted problems, data are transmitted between the signal processing PCB and the LCD control PCB via the low voltage differential signal (LVDS) method, and a shield process and a ferrite core are provided, but these increase production costs.
Further, a power generation block is divided into an image driving power generator, a scaler power generator and a back light driving inverter and each of them is installed on respective PCB blocks, and since the power is supplied to the scaler power generator and then to an inner analog/digital converter or to the image driving power generator, a very high current flows via a cable, which renders the device vulnerable to the EMI.
In addition, since the power generation blocks are scattered on the respective PCB blocks and there is a lot of data transmission between the PCB blocks, many functions are repeated.
Also, since the PCB blocks include three units, digital signals and driving power connections are increased and therefore the cost for solving EMI problems increases. In other words, an additional unit for installing three PCBs and EMI shielding increases the thickness and weight of the product and limits the product design.